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    <meta charset="UTF-8">
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    <title>Document</title>
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    <script>
         
        // 封装函数
        function sum(a,b){
            let gentle = 0
            gentle = a+b
            return gentle
        }
        // 调用函数
        let rem= sum(5,6)
        document.write(rem)
    </script>
</body>
</html>